Historical clue formulations

• Participants in a 140.6-mile race — 2024-08-28
• Certain endurance athletes — 2023-08-06
• Durable athletes — 2007-12-08
• Tireless ones — 2000-01-07
• Triathletes — 1999-12-23
• Herculean athletes — 1998-07-30
• Triathlon athletes — 1994-01-30